Pro Sports

Dan Koppen's knee injury big blow to Denver Broncos' offensive line

Dan Koppen walks out to the field during training camp July 26, 2013 at Dove Valley. (John Leyba, The Denver Post)

For a team that does its business in a place that gets 300 or so days of sunshine each year, the Broncos can't seem to shake the rainy-day blues.

After plenty of off-the-field drama in recent weeks, the Broncos' on-the-field plan took a hit Sunday when center Dan Koppen suffered a torn anterior cruciate ligament in his left knee at training camp. It's a season-ending injury for the Boston College product, who now faces surgery and a long rehab while the Broncos still face signi- ficant roster questions up front.

"You always cringe. You never like to see anybody that's injured severely," coach John Fox said. "But you understand ... it happens."

Koppen, who turns 34 on Sept. 12, signed a one-year, $940,000 contract July 2 as a result of bad injury news when the Broncos discovered J.D. Walton needed additional ankle surgery.

Walton, who suffered a fractured ankle in the Broncos' Week 4 home game against the Oakland Raiders last year, is on the physically unable to perform list and not expected back until late October at the soonest.

Koppen made 13 starts for the Broncos last season, including the playoff loss to the Baltimore Ravens, and the thinking was he could seamlessly fill in for Walton once again this year. But Koppen's season ended in a pileup Sunday while the Broncos were working on their running game.

Soon after the Broncos wrapped up the morning practice, an examination of Koppen's injured knee revealed the torn ACL. Koppen has made 132 regular-season starts during his NFL career. He played for the New England Patriots from 2003-11.

Sunday was just the second time this summer the Broncos practiced in full pads.

"It's always a Catch-22 this time of year," Fox said. "You're trying to get ready for the season and you need to get in pads because you've got to get in shape, yet you're still trying to make sure you have enough guys."

Manny Ramirez, who made 11 starts at right guard for Denver last year, was at center throughout offseason workouts before training camp. But when Walton was forced to have more surgery, Denver signed Koppen and he was quickly put into the starting lineup.

Ramirez, a powerful blocker in the running game, allowed six sacks in man-on-man situations last season, the highest total on the team. Many defensive coordinators in the NFL say the best way to unsettle quarterback Peyton Manning is with pressure up the middle, so any issues at center would certainly impact the Denver offense.

With training camps underway across the league, Steve Vallos and Eugene Amano topped a shallow list of unsigned centers. The Broncos made contact with the representatives for both before coming to contract terms with Vallos on Sunday night. Several personnel executives in the league said Amano, who played nine seasons with the Tennessee Titans, was still looking for the pay of a starter after he spent the 2012 season on injured reserve with a torn triceps.

Vallos, a seventh-round pick by the Seattle Seahawks in the 2007 draft, has played in 42 regular-season games in his NFL career, including nine starts. He was an offense tackle at Wake Forest, but has spent most of his NFL career at guard and center. He is expected to practice with Denver on Monday.

Asked after practice Sunday about Ramirez's transition from guard to center, Fox said: "We need that flexibility. When you pick the offensive line, not just for the season, but even for game day, you have to pick them from the standpoint of some flexibility. You've got to swing guard, center, you've got to swing tackle, guard."

First-year offensive coordinator Adam Gase praised the offensive line's work in the running game after Saturday's practice. It was the first time the Broncos were in full pads this summer. As camp opened, left tackle Ryan Clady said the team's offensive line was poised to have a big season.

"Offensive line, we did well last year," Clady said. "A couple years ago we led the league in rushing. We have some great, young talent and we definitely are going to improve this year."